direction ray目标射线directionn.方向；指导；用法说明；趋势；目标；管理direction changing mechanism转向机构direction finder calibration测向器校正directional pulse modulation定向脉冲调制directional scanning antenna定向扫描天线direction of decisive battle决战Directional cost aggregation方向能量聚集direction-annexed traverse方向附合导线Direction of static friction静摩擦力的方向directionally solidification定向凝固directional antenna assembly定向天线装置